Port of Miami Tunnel Project Gears Up to Go

Port of Miami Tunnel Project Gears Up to Go ~

State of Florida environmental regulators have given the
go-ahead for an ambitious four-year, billion-dollar project to
connect Port of Miami facilities with highway access through a
23-foot-in-diameter tunnel under Biscayne Bay, the
Miami
Herald
reports (“
Florida
gives green light to Port of Miami tunnel
,” by Andres
Viglucci). Major components of the project, including a plan to
retain, purify, and re-use water from the tunnel-boring project and
a proposal to clean and use spoil dirt for beautification and
eco-system recovery on degraded or over-developed islands, have
received Florida Department of Environmental Protection approval,
allowing issuance of the permit.
To dig the tunnel, a consortium of construction companies called
MAT Concessionaire,
LLC
, has acquired a giant custom-built 2,500-ton boring machine
longer than a football field, with a huge, 23-foot disc-shaped
grinding head that weighs 530,000 pounds (above). The machine was
delivered back in June; now, the grinding head has been assembled
and a concrete entry ramp built on Watson Key, an artificial
island, CBS Miami reports (“
Critical
Day In $1B Port Of Miami Tunnel Project
”). Drilling is
set to start as early as this month.
The boring machine has been nicknamed “Harriet,”
reports the Herald (“
Massive
machine comes together to dig port tunnel
,” by Andres
Viglucci). “The cutting head and the circular engine section
will pull a train-like assemblage, including a two-story gantry
resembling a high-tech locomotive, that will contain electrical and
hydraulic systems, a manned command center, mechanic’s shop,
brake room and a chamber that can be sealed to protect 16 people in
case of fire or other emergencies,” the paper reports.
“The entire machine will be powered through a connection to
the electrical grid.”
As it tunnels under the bay at a rate of about four feet per
hour, the giant machine will inject sealant grout into the porous
limestone rock, and set curved pre-cast concrete panels in place to
form the tunnel wall’s permanent structure. Upon reaching the
other side of the bay, engineers will disassemble the beast,
reassemble it, and cut a return tunnel — completing the work,
if all goes as planned, sometime in 2014. Then, say Florida
Department of Transportation officials, the tunnel will begin
decades of service life, ensuring long-term access to the port (see
video, below).